Two former Parramatta Eels players are accused of harbouring semi-automatic weapons and possessing more than half-a-million dollars in cash after dramatic arrests in Sydney's Centennial Park yesterday.

"We believed the 29-year-old placed himself and the search teams at risk through his lack of planning and preparation, and through carrying inadequate provisions," NSW Police Force Rescue commander Brenton Charlton said.

"The man had with him a kilo of potatoes and naan bread."

Mr Charlton said the man's intended route through remote terrain would have been extremely difficult to complete safely and it had taken much longer than he had estimated.

"Getting the basics right with trekking is so easy - all people have to do is notify the police or other responsible person of their trip intention and carry a personal locator beacon," he said.

"Making use of available technology, together with some commonsense trip preparation, could mean the difference between life or death."

The man has been given a $500 infringement notice for "engage in activity that risks the safety of self/others".